version 0.2.1

repo url: https://github.com/fabiolune/shared-utils

shared-utils

dotnet Quality Gate Status codecov Mutation testing badge

A collection of .NET libraries that provide shared building blocks for web applications. The solution follows a functional programming style built on top of LanguageExt and targets net8.0, net9.0 and net10.0.

Solution structure

shared-utils/
├── Fl.Shared.Utils.Components.Web.Models/   # Shared model records (DTOs)
├── Fl.Shared.Utils.Components/              # Logging & web middleware components
├── Fl.Shared.Utils.Mappers/                 # Mapper abstractions and implementations
└── tests/
    ├── Fl.Shared.Utils.Components.Unit.Tests/
    └── Fl.Shared.Utils.Mappers.Tests/

Projects

Fl.Shared.Utils.Components.Web.Models

Lightweight model library with no external dependencies. Defines the shared records used by the other projects:

Type Description
ErrorResponse JSON error payload ({ "message": "..." })
RoutingConfiguration Optional URL base-path configuration
ServiceDescription Service name and version metadata

Fl.Shared.Utils.Components

The main component library. Provides reusable infrastructure for logging and ASP.NET Core web pipelines.

Logging

Component Description
SerilogConfiguration Configuration record for Serilog (level, overrides, environment, system, customer)
LoggerConfigurationExtensions Default Serilog setup with CompactJson console output
HostBuilderExtensions AddSerilogLogging on IHostBuilder
LoggingWebApplicationBuilderExtensions AddSerilogLogging on WebApplicationBuilder
EitherLoggingExtensions TeeLog on Either<Error, T> / EitherAsync<Error, T>
ErrorExtensions Convert a LanguageExt.Common.Error to a logging Action

Web middleware

Middleware Description
JsonExceptionHandlerMiddleware Catches unhandled exceptions → HTTP 500 JSON
RequestLogContextMiddleware Enriches Serilog context with CorrelationId
TraceLogContextMiddleware Enriches Serilog context with SpanId / TraceId
ServiceDescriptionMiddleware Serves service metadata at GET /internal/description

Key extension methods

Method Description
services.AddDefaultComponents(config) Registers all default middleware and services
app.UseDefaultMiddlewares() Wires up the default middleware pipeline
services.AddEndpointDefinitions(...) Scans assemblies for IEndpoint implementations
app.UseEndpointDefinitions() Calls DefineEndpoints on all registered IEndpoints
app.UseRoutingBasePath() Applies the configured URL base path

Fl.Shared.Utils.Mappers

Mapper abstractions and a default HTTP-result implementation.

Type Description
IMapper<T1, T2> Generic single-direction mapping contract
IApiResultMapper<T> Maps Option<T> and Error to ASP.NET Core IResult
DataHttpContentMapper<T> Default implementation: Some → 200, None → 404, Error → 500

Quality

Concern Tooling Target
Unit testing NUnit + NSubstitute + Shouldly —
Code coverage Coverlet + Codecov 100 %
Mutation testing Stryker.NET (advanced level) —
Versioning GitVersion — ContinuousDelivery on main —

Key dependencies

Package Purpose
LanguageExt Functional types (Either, Option, Error)
Serilog Structured logging
CorrelationId HTTP correlation ID propagation
Scrutor Assembly scanning for IEndpoint
Fl.Functional.Utils Internal functional utilities (Tee, Map, MakeOption, …)
Fl.Configuration.Extensions Strongly-typed configuration helpers
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